Gasoline composition



United States Patent 3,179,506 GASQLINE COMPOSITION Hubert T. Henderson, Walnut Creek, Calif., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed May 2, 1952, Ser. No. 191,730 11 Claims. (Cl. 44-66) This application is a continuation-impart of pending application Serial No. 120,932, now abandoned, filed June 30, 1961.

This invention relates to an improved gasoline composition for spark ignition internal combustion engines, more particularly to a gasoline composition with improved knock resistance.

Knock in spark ignition engines is generally considered to be caused by an abnormally rapid combustion of an unburned fuel-air mixture in front of the normal flame front. A severe pressure unbalance due to this rapid combustion process sets up shock waves which impinge upon the cylinder walls and pistons to produce the characteristic metallic knocking noise.

The need for high quality fuels, having increased resistance to knock over a wide range of engine operating conditions is of paramount significance in current engine operation. Careful refining and blending of fuel components can produce a fuel of sufficiently increased knock resistance to satisfy engine requirements under certain stressed conditions. The resistance to detonation by such fuels is even further augmented by the addition of organometallic antiknock agents such as lower alkyl lead com positions, tetraethyllead (TEL), for example, and various other organo-metallic compositions such as methylcyclopentadienyl manganese tricarbonyl. TEL is widely used today for the improved antiknock quality which it imparts over a broad range of engine operating conditions. The use of TEL, however, has limitations, especially that each successive increment of TEL added to the fuel produces only a fraction of the improvement in antiknock rating obtained with the addition of the preceding increment. Moreover, certain fuels for spark ignition engines, particularly those containing high amounts of aromatic and/or olefinic components, respond rather poorly to TEL, particularly at the normal upper limit of about 4.0 grams of lead/gallon of fuel in automotive engines and about 7.0 grams of lead/gallon of fuel in aviation engines.

Resistance to knock is evaluated in terms of octane numbers. When the octane number of a motor gasoline fuel is raised there is generally a concomitant decrease in the susceptibility of such fuel to further octane number improvement by the addition of organo-metallic antiknock agents. Therefore, it becomes less economical to obtain further resistance to knock by employing organometallic antiknock agents in higher concentrations with higher octane fuels.

., It is well known in the art that certain organic materials such as tertiary butyl acetate can be employed as cooperative octane improvers for certain organo-metallic antiknock agents, such as TEL in gasoline. These organic materials cooperate with the antiknock agent to increase its effectiveness in gasoline and can be referred to as co-antiknock agents. Generally, these co-antiknock agents should distribute along with the antiknock agent and be effective over a wide range of co-antiknock to antiknock mole ratios. In addition, a co-antiknock agent should preferably have the following physical properties: (1) be a water-white liquid, (2) boil in the motor fuel distillation range, (3) be miscible in gasoline at temperatures from the freezing point to the boiling point, (4) be practically insoluble in water, and (5) be no more toxic than the hydrocarbons and other additives in the motor fuel.

It is an object of this invention to provide improved gasoline fuel compositions containing octane improving amounts of organo-metallic antiknock agents and octane improving amounts of certain organic co-antiknock agents. It is also an object of this invention to extend the effectiveness of certain organo-rnetallic antiknock additives. It is a further object of the invention to increase the detonation resistance of gasolines containing such additives without increasing either the toxicity of the fuel compositions or its tendency to lay down combustion chamber deposits. A still further object of the invention is to provide improved gasoline fuel compositions in which the efiectiveness of certain antiknock and co-antiknock additives is increased in an economical manner. It is a further object of the invention to provide an improved co-antiknock agent also having scavenger properties. Other objects will be apparent in the description of the invention.

It has been disclosed in copending applications 79,508, now abandoned, and 79,535, all filed December 30, 196i), and 97,451, filed March 22, 1961, that when certain classes of organic esters, composed solely of carbon, hydrogen, and oxygen, are added in small but critical amounts to high octane motor fuels containing organo-metallic antiknock agents, such as lower alkyl lead compositions and the class of manganese compounds disclosed in the US. Patent to Brown et al. 2,818,417, December 31, 1957, that the octane number of the fuel compositions is unexpectedly raised by as much as 2 octane numbers, even though in the absence of these antiknock agents, substantially no octane number benefit is obtained by the addition of these esters to the motor fuel. Moreover, both Research Method octane number (RON and Motor Method octane number (MON), are increased. (By Research and Motor Methods for obtaining octane number, reference is made to ASTM test designations D-9Q8-55 and D35753, respectively.) These organic esters produce this cooperative (co-antiknoclc) effect when combined with octane-improving amounts of certain organo: metallic antiknock agents such as TEL. Moreover, the above-referenced co-antiknock agents were shown to have volatility characteristics similar to those of TEL and other organo-metallic antilrnockagents and tend to maldistribute with the antiknock agent throughout the cylinders. In addition, these co-antiknock agents exhibit optimum gains over a wide range of co-antiknock agent to organo-metallic antiknock agent mole ratios, i.e., 5:1 to 20:1. i

It has now been discovered that when the above-referenced co-antiknock agents composed of carbon, hydrogen, and oxygen have added thereto one or more electronegative atoms, e.g., halogen atoms, to the beta position of the alcohol moiety, these materials unexpectedly produce a co-antiknock effect at a significantly lower octane level. That these co-antiknock agents containing electronegative groups would produce a cooperative effect with organo-metallic antiknock agents in certain fuel compositions is not wholly unexpected in view of the referenced copending applications. However, heretofore, co-antiknock materials such as ethyl acetate were disclosed and claimed, for example, in copending application 97,451, filed March 22, 1961, to be effective only at relatively high RON, e.g., 0.75% vol. ethyl acetate, was shown to produce a ARON of 0.8 in isooctane having an R-3 of 115.5; Whereas at an R3 of 102, 0.75% vol. ethyl acetate produced no co-antilmock effect. It has now been found that the addition of an electro-negative atom, such as certain halogen atoms to the beta position of the alcohol moiety of ethyl acetate, results in a similar eo-antiknock efiect (ARON of about 0.5) but in a gasoline having an R-3 of about 100.8. Therefore, when the co-antiknock agents previously disclosed and claimed contain one or 'more electro-negative groups such as fluoro, chloro, cyano, and hydroxyl radicals in the beta position of the alcohol moiety, they will produce expected co-antiknock effects with certain organo-metallic antiknock agents at unexpectedly reduced octane levels. 7

The co-antiknock agents of the invention are gasolinesoluble materials composed of carbon, hydrogen, and oxygen, containing at least one electro-negative atom or group per molecule in the beta position of the alcohol moiety. These co-antiknock compounds can be more readily defined as an ester of an organic monocarboxylic acid and an alkanol having at least one hydroxyl group,

'each hydroxyl group being directly connected to a carbon atom which is in turn directly connected to a carbon atom having an electro-negative substituent; that is, the electronegative substituent is on the beta carbon to the hydroxyl group of the alcohol moiety. The organic monocarboxylic acid is further defined as an aromatic, olefinically unsaturated, or saturated monocarboxylic acid consisting solely of carbon, hydrogen and oxygen. The alcohol moiety can contain one or more hydroxyl groups, with polyhydroxy moieties such as hexylene glycol and pinacol, and monohydroxy moieties such as ethanol, n-propanol and n-butanol being preferred. The electro-negative substituent can be a halogen atom such as fluorine or chlorine, or a nitro-containing radical such as a nitro or cyano group or a hydroxy radical.

These co-antiknock materials can be more readily defined by the following structural formula:

wherein R R and R, can be hydrogen atoms, low molecular weight alkyl radicals containing up to 8 carbon atoms, low molecular weight alkenyl radicals containing up to 8 carbon atoms, low molecular weight alkenyl radicals containing up to 6 carbon atoms, low molecular Weight alkoxy radicals containing up to 8 carbon atoms, cycloalkyl radicals containing up to carbon atoms, aryl radicals, arylalkyl radicals containing up to 15 carbon atoms, R can also be X when y is equal to 1, and X is an electronegative radical beta to the hydroxylic carbon atom where for each ester unit CH CH3 CH CH The mechanism by which the additives of Formula I function is not thoroughly understood. However, it is evident from the data set forth in Table I below that these electro-negative containing co-antiknock agents unexpectedly produce co-antiknock effects in gasoline fuel compositions having an RON from about 8 to about 13 numbers lower than the fuel composition containing similar coantiknock agents which did not have an electro-negative atom in the beta position of the alcoholmoiety.

TABLE I Base Fuel Per- Research g. Lead Co-Antiknock Agent cent by Base Fuel Octane ARON per gal. Weight Number as TEL Level (RON) 50% v. cat. cracked gasoline. Ethyl acetate 0.7 25% v. isooetane 102 0.0 3.19

25% v. catalytic reformate- Do 0. 75 Isooctane 115. 5 0.8 3.19

33%% v. -250 eat. cracked gasoline 2-Chloroethyl acetate 0.4 33%% v. isooctane 100. 8 0. 5 3. 19

33%% v. catalytic reformate 33%% v. 0 -250 cat. cracked gasollne. Do 0.2 33%% v. isooctane 100. 8 0. 4 3.19

33%% v. catalytic r rmat B-Cyanoethyl acetate r. 0. 4 reiformageu t 100. 4 0. 7 3.19

a a a y re re orma c con ammg Z-Hydroxyethyl acetate-.. 0.8 isopmpyl alcohcl me. o 0. 4 3.19

Quite unexpectedly it was found that the co-antiknock effect of the materials of Formula I was further limited by the position of the electro-negative radical in the compound. It is readily apparent from the data set forth in Table II below that the co-antiknock effect is critically limited to those additives wherein the electro-negative radical is in the beta position on the alcohol moiety. For example, when the electro-negative substituent is at tached to the acid moiety, e.g., ii-iodopropionic acid or ethyl trichloroacetate proknock effects in excess of 11 RON result.

It has further been found that the materials of Formula I are not effective as co-antiknock agents unless the hydroxylic carbon atom contains at least one hydrogen atom; that is if the hydroxylic carbon atom is a tertiary carbon atom the x substituent in the beta position relative thereto has been found to render the additive proknock. In addition it has further been found that the beta carbon atom must also contain at least one hydrogen atom for if the beta carbon atom is trisubstituted with electro-negative groups it also produces a proknock effect.

The electro-negative radical, X, of Formula I can be a electro-negative radical Which will not adversely effect the solubility of the additive in gasoline and which will not significantly alter any of the other preferred properties of the additive such as: the co-antiknock properties, miscibility with gasoline at temperatures from the freezing point to the boiling point, solubility in water, toxicity and boiling range.

Preferred electro-negative radicals include halogen, nitro, cyano and hydroxy radicals. Particularly preferred are the halogen radicals, chlorine and fluorine.

In addition to providing a novel co-antiknock agent which is effective at unexpectedly reduced octane levels, the use of chlorine as the electro-negative radical in the co-antiknock additive of Formula I also provides a novel method of introducing a lead scavenging compound into the combustion chamber. That is, upon decomposition of the parent co-antiknock compound the chlorine will serve as scavenging materials, thereby avoiding the necessity of introducing a separate scavenging additive such as ethylene dichloride (a conventional additive used in gasoline additive packages).

The co-antiknock agents of Formula I are not effective in all gasoline motor fuels containing organo-metallic antiknock compounds. It has been found that in leaded gasoline an octane-improving amount of tetraalkyllead equal to about 0.1 gram of lead per gallon of fuel must be present in order to produce a significant cooperative effect. The lead concentration may be as high as about 18.6 grams of lead per gallon of fuel. It has been found that organo-rnanganese compounds should not be used with the co-antiknock substances of the invention at higher concentrations than about 2.0' grams of manganese per gallon of fuel, but the co-antiknock compounds are highly effective in fuels containing any octane-improving amount of organo-manganese less than about 2.0 grams of manganese per gallon of fuel. Generally, a minimum octane number improving amount of organo-manganese is an amount corresponding to about 0.05 gram of manganese per gallon of fuel. It is preferred that the fuel compositions of this invention contain at least 0.2 gram of lead per gallon of fuel or from 0.05 to 1.75 grams of manganese per gallon of fuel. The fuel can contain mixtures of the two antiknock materials so long as the concen trations of each is within the foregoing limits. Further the fuel can contain mixtures of the herein defined co-anti knock agents, for example, 0.2% v. Z-fluoroethyl acetate and 0.4% v. 2-chloroethyl acetate added to a fuel having an RON of about 100 and containing 3.136 grams lead. as TEL produces a significant co-antiknock effect.

When improving the octane rating of fuels, the cost per unit octane number. increase becomes greater at higher octane levels, requiring more extensive refining and con- Version mthods. Generally, the effectiveness of the antiknock agents decreases with each additional increase in.

antiknock concentration. For example, TEL ceases to be economical above about 3 to 4 grams of lead per gallon.

of fuel. It is at this point that the class of co-antiknocks as hereindefined are effective. For example, these co-.

antiknock agents are effective in producing significant increases in the octanerating of gasolines having RON of from about 100 to about 115, whereas conventional processing or doping costs to produce a corresponding octane increase is excessive. Moreoyenthese co-antiknocl: additives are also effective in the to 102 octane number range, Where conventional processing, and the use of increased concentration of antiknock agents is often un desirable.

The co-antiknock agents of Formula I act as cooperative high level octane improvers, that is they display a coantiknock effect only when combined with certain organometallic antiknock agents; in high octane gasolines, in

factpthe co-antiknock effect is directly related'to the type and concentration of the particular antiknocl; agent pres:

out. When added to a base hydrocarbon fuel which did not contain an antiknock agent, the class of compounds of Formula I were found to have no antiknock effect.

Water insolubility is an important physical property of co-antiknock agents. Generally, commercial gasolines contain a small amount of dissolved water (from .005 to 0.2% by volume). Such water is, of course, derived from the previous processing of the gasoline and gasoline precursors, for example, crude desolvent and steam stripping. Thus when commercial gasolines undergo cooling and storage or during transportation, the dissolved water tends to precipitate out of the fuel. It is therefore important that the co-antiknock additive contained in gasoline be It is preknock agent in the base hydrocarbon fuel should be at least about 50% by weight while its solubility in water at normal storage temperatures should not exceed about 5% by weight. Z-chloroethyl acetate, for example, is nearly insoluble in water and highly soluble in the base fuel.

The co-antiknock materials of the invention are generally efiective in pure hydrocarbon (i.e., less than 1% v. contaminants) in the gasoline boiling range, having a RON (with 3 cc. TEL/ gal.) from about 90 to about 125. Mixtures of pure hydrocarbons and/or of conventional gasoline refining process streams are likewise suitable, provided the RON (3 cc. TEL/ gal.) of the finished blend falls within the approximate 90 to 125 range. Within the limits of the afore stated octane level restrictions, catalytic reformate, catalytically and thermally cracked gasolines, and motor alkylates are suitable to the invention. Especially preferred as blending components, however, are light aviation alkylates, isomerizates, high severity reformates, reformate extracts, and pure aromatics such as benzene, toluene and xylenes. It is further preferred that the finished gasoline contain appreciable amounts (i.e., 5 to 10% v. minimum) of each of two or more hydrocarbon types. Where there are only two hydrocarbons in a preferred embodiment of the invention, the hydrocarbon fuel is selected from the group consisting of mixtures of parafiins and olefins, mixtures of olefins and aromatics, mixtures of highly branched parafiins. In addition, certain oxygenated hydrocarbons such as lower alkyl alcohols and certain lower dialkyl ethers can be used in the gasoline in concentrations up to 20% by volume.

Within the foregoing limits of gasoline composition and antiknock concentration, the co-antiknock materials of the invention are efiective in concentrations as low as 0.1% by volume. However, at least 0.2% by volume is preferred since substantial increases in both Motor Method and Research Method octane numbers are obtained by using at least this amount. The upper limit beyond which no substantial further increase in octane number is obtained by either the Research or Motor Method varies somewhat among the various effective co-antiknock agents as well as with the hydrocarbon composition and the particular antiknock material used. Preferred concentrations are from about 0.2 to about 1.0% by volume. Though greater amounts may be added, it has been found that little additional benefit is obtained by adding more than about 1.0% by volume. Moreover, certain compounds of Formula I exhibit proknock effects at concentrations above about 1.5% by volume.

It is to be understood that the order of mixing the various constituents of the compositions of the invention is immaterial. For example, the co-antiknock compound may be added to gasoline which already contains an organo-metallic antiknock compound. Likewise, the co-antiknock and antikock compounds may be first mixed, stored and handled as a concentrate and added to the gasoline at a later time. A gasoline additive concentrate of this latter type may also contain halogen scavenger compounds when halogen is not present in the co-antiknock agent. In addition to the halogen containing lead scavengers, the fuel compositions of the invention can and ordinarily will contain other additives, for example, dyes, spark plug anti-foulants such as tricresyl phosphate, di-

methyl xylyl phosphate, and diphenyl cresyl phosphate, combustion modifiers such as alkyl boronic acids and lower a kyl phopshates and phosphites, oxidation inhibitors such as N,N-ditertiarybutyl-4-methylphenol, metal deactivators such as N,N-disalicylal-1,2 propanediamine, and rust inhibitors such as polymerized linoleic acids and N,C-disubstituted imidazolines, and the like. Under some' circumstances it may be desirable to mix antiknock comf'p'ound with the co-antiknock compound in the desired relative porportions and handle or store this mixture with or without stabilizers, anti-fouling compounds, in- 'hibitors, etc., as a concentrate for incorporation with the other components of the ultimate fuel composition.

In addition to TEL, the co-antiknock agents of Formula I are also effective in fuels containing other organo-metallic compounds as antiknock agents. These include tetraalkyllead compounds such as tetramethyllead, tetra-n propyl lead, methyl triethyllead, ethyl trimethyllead, dimethyl diethyllead and mixtures thereof and other organometallic materials such as cyclopentadienyl nickel nitrosyl, methylcyclopentadienyl manganese tricarbonyl and related materials, tris-(acetylacetonate) iron-II, nickel Z-ethylhexyl salicylate, bis-(N-butyl salicylaldimine) nickel and vanadium acetylacetonate. However, the herein defined additives do not exhibit co-antiknock activity with all organo-metallic antiknock agents. Moreover, the efiectiveness of these co-antiknock agents varies considerably with each organo-metallic material. Tetraalkyllead, cyclopentadienyl nickel nitrosyl, methylcyclopentadienyl manganese tricarbonyl and tris-(acetyl-acetonate) iron- III are therefore preferred organo-metallic antiknock agents for the vfuel compositions of the invention.

The following examples of motor gasoline fuel compositions are suit-able for use according to the invention.

Example 1 Catalytic reformate percent v-.. 99.30 Tetraethyllead g. lead/gaL- 2.7 2-chloroethyl acetate percent v 070 Example ll Straight run gasoline having a RON of about 99 percent v 99.33 Ethyl trimethyllead g. lead/gaL- 2.0 2,2-dichloroethyl acrylate percent v 0.67

Example III Motor gasoline containing approximately:

v. olefins, 20% v. naphthalenes, and having a RON of about 100 percent v 99.3 Tetraethyllead g. lead/gal 0.2 1-chloro-2-butyl methacrylate percent v 0.7

Example IV Motor gasoline containing: 80% v. isooctane, 20%

v. pentenes percent v 99.1 Diethyl dimethyl lead g. lead/gaL- 1.0

. CH3 CH3 +=o =0 (I) V 0 -.percent v 0.9 H-o--oH,-b-0H HC-OH HCOH Iii H Example V Motor gasoline containing: 80% v. ethylbenzene,

20% v. naphthenes percent v 99.2 Methylcyclopentadienyl manganese tricarbonyl g. Mn/gaL- 0.5 2-hydroxy n-octyl methacrylate percent v 0.8

9 Example VI Catalytic reformate percent v 99.3 Tris-(acetylacetonate) iron-HI g. iron/gal 0.6 Z-cyano-isopropyl ethacrylate percent v 0.7

Example VII Catalytic reformate percent v 98.5 Nickel 2-ethylhexyl salicylate g. nickel/gal 1.0

CH3 CH3 1 :0 O ..pereent v 1.5 H+CH2-b-orn 010-11 H -01 Example VIII Catalytic reformate percent v 99.5 Vanadium acetylacetonate g. vanadium/gal 1.0 2-cyano,2-chloroethyl acrylate percent v..- 0.6

Example IX Catalytic reformate percent v 99.5 Mixture of: Tetramethyllead 5.7% w., trimethylethyl lead 23.8% w., dimethyl diethyl lead 37.5% w., methyl triethyl lead 26.2% w., tetraethyllead 6.8% w. g. lead/gal; 3.186 Z-fiuoro-ethyl methacrylate per cent v 0.5

Example X 50% v. isooctane, 50% v. ethylbenzene percent v 99.5 Mixture of: Tetramethyllead 30.0% w., trirnethyl ethyl lead 42.2% w, dimethyl diethyl lead 22.2% w., methyl triethyl lead 5.2% w., tetraethyllead 0.5% W g. lead/gal 3.186 2,2-diiiuoro-ethyl acrylate percent v 0.5

I claim as my invention: 1. Gasoline for use in spark ignition internal combustion engines consisting essentially of a hydrocarbon base fuel, an octane-improving amount of an organometallic antiknock agent selected from the group consisting of tetraalkyllead, cyclopentadienyl nickel nitrosyl, methylcyclopentadienyl manganese tricarbonyl, tris- (acetylacetonate) iron-III, nickel Z-ethylhexyl salicylate, and an octane number improving amount of a gasoline soluble co-antiknock agent having the structural formula:

Where R R and R are members selected from the group consisting of hydrogen atoms, low molecular Weight alkyl radicals containing up to .8 carbon atoms, low molecular Weight alkenyl radicals containing up to. 6 carbon atoms, low molecular Weight alkoxy radicals containing up to 8 carbon atoms, cycloalkyl radicals containing up to 15 carbon atoms, aryl radicals, arylalkyl radicals containing up to 15 carbon atoms, and wherein X is an electro-negative radical beta to the hydroxylic carbon atom where, for each ester unit 10 X is selected independently from the electro-negative group consisting of fluoro and chloro radicals, w is an integer from 1 to 2, y is zero or an integer from 1 to 7, and 2 represents an integer from 1 to 5.

2. The gasoline of claim 1 in which the co-antiknock agent is 2 -chloroethylacetate.

3. A gasoline composition of claim 1 containing up to 20% volume of oxygenated hydrocarbons selected from the group consisting of lower dialkyl ethers and lower alkyl alcohols.

4. A hydrocarbon fuel of the gasoline boiling range for use in spark ignition internal combustion engines having a Research Octane Number from about to about and containing an octane-improving amount of an organo-metallic antiknock agent selected from the group consisting of tetraalkyllead, cyclopentadienyl nickel nitrosyl, methylcyclopentadienyl manganese tricarbonyl, tris- (acetylacetonate) iron-HI, nickel 2-ethylhexyl salicylate, bis-(N-butyl salicylaldimine) nickel and vanadium acetylacetonate, and at least 0.1% by volume of a gasoline soluble co-antiknock agent having the structural formula:

0 H s C(CH2) H-( (X) (R2)2w Z Where R R and R are members selected from the group consisting of hydrogen atoms, low molecular weight alkyl radicals containing up to 8 carbon atoms, low molecular Weight alkenyl radicals containing up to 6 carbon atoms, low molecular weight alkoxy radicals containing up to 8 carbon atoms, cycloalkyl radicals containing up to 15 carbon atoms, aryl radicals, arylalkyl radicals containing up to 15 carbon atoms, and wherein X is an electro-negative radical beta to the hydroxylic carbon atom where, for each ester unit X is selected independently from the electro-negative group consisting of fiuoro and chloro radicals, w is an integer from 1 to 2, y is zero or an integer from 1 to 7, and z represents an integer from 1 to 5.

5. A gasoline motor fuel composition consisting essentially of gasoline boiling range hydrocarbons selected from the group consisting of mixtures of paraffins and olefins, mixtures of olefins and aromatics, and mixtures of parafiins and aromatics; an octane-improving amount of an organo-metallic antiknock agent selected from the group consisting of tetraalkyllead, cyclopentadienyl nickel nitrosyl, methylcyclopentadienyl manganese tricarbonyl, tris-(acetylacetonate) iron-III, nickel Z-ethylhexyl salicylate, bis-(N-butyl salicylaldimine) nickel, and vanadium acetylacetonate, and an octane improving amount of a gasoline soluble co-antiknock agent having the structural formula:

. 11 r Where R R and R are members selected from the group consisting of hydrogen atoms, low molecular weight alkyl radicals containing up to 8 carbon atoms, low molecular weight alkenyl radicals containing up to 6 carbon atoms, low molecular weight alkoxy radicals containing up to 8 carbon atoms, cycloalkyl radicals containing up to 15 carbon atoms, aryl radicals, arylalkyl radicals containing up to 15 carbon atoms, and wherein X is an electro-negative radical beta to the hydroxylic carbon atom Where, for each ester unit X is selected independently from the electro-negative group consisting of tluoro and chloro radicals, w is an integer from 1 to 2, y is zero or an interger from 1 to 7, and 2 represents an integer from 1 to 5.

6. The gasoline motor fuel composition of claim 5 in which the gasoline boiling range hydrocarbons are mixtures of parafifins and olefins.

7. The gasoline motor fuel composition of claim 5 in which the gasoline boiling range hydrocarbons are mixtures of oler'ins and aromatics.

8. The gasoline motor fuel composition of claim 5 in which the gasoline boiling range hydrocarbons are mixtures of paraifins and aromatics.

9. A gasoline motor fuel composition consisting essentially of isooctane, an octane-improving amount of tetraethyllead and an octane number improving amount of a gasoline soluble co-antiknock agent having the structural formula:

where R R and R are members selected from the group consisting of hydrogen atoms, low molecular weight alkyl radicals containing up to 8 carbon atoms, low molecular Weight alkenyl radicals containing up to 6 carbon atoms, low molecular weight alkoxy radicals containing up to 8 carbon atoms, cycloalkyl radicals containing up to carbon atoms, aryl radicals, larylalkyl radicals containing up to 15 carbon atoms, and wherein X is an electro-negative radical beta to the hydroxylic carbon atom where, for each ester unit X is selected independently from the electro-negative group consisting of fiuoro and chloro radicals, w is an integer from 1 to 2, y is zero or an integer from 1 to 7, [and z represents an integer from 1 to 5.

It). A gasoline motor fuel composition consisting essentially of ethylbenzene, an octane-improving amount of tetramethyllead and ran octane improving amount but not more than 1.5% v. of the fuel of a gasoline soluble ,co-antiltnock agent having the structural formula:

where R R and R are members selected from the group consisting of hydrogen atoms, low molecular Weight alkyl radicals containing up to 8 carbon atoms, low molecular weight alkenyl radicals containing up to 6 carbon atoms, low molecular Weight alkoxy radicals containing up to 8 carbon atoms, cycloalkyl radicals containing up to 15 carbon atoms, aryl radicals, arylalkyl radicals containing up to 15 carbon atoms, and wherein X is ian electro-negative radical beta to the hydroxylic carbon atom where, for each ester unit X is selected independently from the electro-negative group consisting of fluoro and chloro radicals, w is an integer from '1 to 2, y is Zero or an integer from 1 to 7, and 1 represents an integer from 1 to 5.

11. A gasoline additive concentrate composition consisting essentially of an octane number improving amount of tall organo-meta-llic antiknock agent selected from the group consisting of tetraalkyllead, 'cyclopentadienyl nickel nitrosyl, methylcyclopentadienyl manganese tricarbonyl, tris-( acetylacetonate) iron-III, nickel 2-ethy1hexyl salicylate, bis- (N-butyl salicyl-aldimine) nickel, and vanadium acetylacctonate, and an octane number improving amount of a gasoline soluble co-antiknock agent having the structural formula:

Where R R and R are members selected from the group consisting of hydrogen atoms, low molecular weight alkyl radicals containing up to 8 carbon atoms, low molecular weight alkenyl radicals containing up to 6 car-hon atoms, low molecular weight alkoxy radicals containing up to 8 carbon atoms, cycloalkyl radicals containing up to 15 carbon atoms, aryl radicals, aryltalkyl radicals containing up to 15 carbon atoms, and wherein X is an electro-negative radical beta to the hydroxylic carbon atom Where, for each ester unit no x w X is selected independently from the electro-negative group consisting of fluoro and chloro radicals, w is an integer from 1 to 2, y is zero or an integer from 1 to 7, and z represents an integer from 1 to 5, the mole ratio of eo-antiknock vagent to organo-meta1lic antiknock agent being from 5 :1 to 20:1.

References Cited by the Examiner UNITED STATES PATENTS 5 3/35 Jaeger 44-70 8/ 40 Lipkin 44-70 1/41 Helm 44-7O 10/44 Ross et a1 44-80 10 10/47 McCulloch 44-69 12/57 Brown et a 44-68 14 3,021,205 2/62 Chafetz et a1. 44-69 3,087,801 4/63 Eekert et a1. 44---70 FOREIGN PATENTS 837,965 11/38 France.

OTHER REFERENCES Improved Motor Fuels Through Selective Blending, by Wagner et al., paper presented before the 22nd Annual Meeting of the American Petroleum Institute, November 7, 19 41, 19' p DANIEL E. WYMAN, Primary Examiner. 

1. GASOLINE FOR USE IN SPARK IGNITION INTERNAL COMBUSTION ENGINES CONSISTING ESSENTIALLY OF A HYDROCARBON BASE FUEL, AN OCTANE-IMPROVING AMOUNT OF AN ORGANOMETALLIC ANTIKNOCK AGENT SELECTED FROM THE GROUP CONSISTING OF TETRAALKYLLEAD, CYCLOPENTADIENYL NICKEL NITROSYL, METHYLCYLOPENTADIENYL MANGANESE TRICARBONYL, TRIS(ACETYLACETONATE) IRON-III, NICKEL 2-ETHYLHEXYL SALICYLATE, AND AN OCTANE NUMBER IMPROVING AMOUNT OF A GASOLINE SOLUBLE CO-ANTIKNOCK AGENT HAVING THE STRUCTURAL FORMULA: 